Qinghai Lake is the largest inland lake in China. It is a closed-drainage saline lake located at 3194m above sea level in the northeastern Qinghai-Xizang (Tibet) Plateau. Qinghai Lake region, about 36°15' -38...Qinghai Lake is the largest inland lake in China. It is a closed-drainage saline lake located at 3194m above sea level in the northeastern Qinghai-Xizang (Tibet) Plateau. Qinghai Lake region, about 36°15' -38°20' N and 97°50, - 101°20' E,is a closed basin展开更多
Spring land surface temperature/subsurface soil temperature over the Qinghai-Xizang Plateau(QXP)substantially impacts downstream precipitation on subseasonal timescales.However,how well can climate models reproduce th...Spring land surface temperature/subsurface soil temperature over the Qinghai-Xizang Plateau(QXP)substantially impacts downstream precipitation on subseasonal timescales.However,how well can climate models reproduce this impact and its assoicated interannual variation remains unclear.This study utilized the Regional Climate Model(Reg CM)Version 4.7 coupled with the Community Land Model(CLM)Version 4.5(Reg CM4.7-CLM4.5)to investigate the impact of May QXP soil temperature anomalies on June precipitation in eastern China.Causes for different precipitation responses to land surface/subsurface conditions and atmospheric background states in four years were analyzed.The results indicate that warm surface and soil temperature anomalies over the QXP in May led to increased precipitation in the southern Yangtze River basin(SYRB)in June.Due to soil temperature memory,the QXP warming persisted into June,sustaining a negative geopotential height anomaly at 500 h Pa above the QXP.Concurrently,negative and positive height anomalies developed over northern China and the Sea of Japan.The corresponding cyclonic anomaly in the mid-to-lower troposphere over QXP enhanced monsoonal moisture transport in May,and the persistent soil temperature anomaly over QXP sustained moisture convergence over southern China in June,resulting in increased precipitation there.Of the four years examined,both the precipitation response in the SYRB and the intensity of the associated wave train pattern are the strongest in 1998.The combined effect of land surface conditions in May and the atmospheric circulation background in June influenced the precipitation responses.Thermal conditions affected snow cover variations and consequently the radiative balance in the western QXP,causing stronger low-level atmospheric responses in 1998 compared to other years.Additionally,the position of the westerly jet influenced the propagation of atmospheric anomalies,contributing to the different responses in the mid-to-high troposphere.The above findings underscore the role of spring soil temperature anomalies over the QXP as a source of predictability for precipitation in eastern China at the subseasonal timescale.展开更多
In current research on the Anthropocene, assessing the impact of human activities via stratigraphic records of sediments and demarcating the Anthropocene epoch globally are critical scientific issues that urgently nee...In current research on the Anthropocene, assessing the impact of human activities via stratigraphic records of sediments and demarcating the Anthropocene epoch globally are critical scientific issues that urgently need to be addressed. The northeastern Qinghai-Xizang Plateau(QXP), where humans first settled permanently in large numbers in the QXP, has varying sedimentary environments that are extremely sensitive to human activities. In contrast to other regions of the QXP, the northeastern sector boasts a richer array of climatic and environmental reconstruction sequences. This distinctive feature renders it an exemplary locale for investigating the stratigraphic boundary of the Anthropocene. Through in-depth analysis and integration of existing paleoclimate and paleoenvironment sequences in the northeastern QXP, we draw the following conclusions:(1) Throughout the past millennium, the impact of human activities on the environment of the northeastern QXP has become increasingly significant, especially in the past 200–300 years, gradually overshadowing climatic factors.(2) Since AD 1950,multiple physicochemical indicators related to human activities in the northeastern QXP have shown exponential growth,forming a distinct peak within the past millennium and clearly depicting the global “Great Acceleration” phenomenon and its development process.(3) Intensified human activities have driven swift environmental shifts and “decoupled” the interplay between climatic variations and the ecological environment, propelling the northeastern QXP into the “Early Anthropocene”from the “Late Holocene”. On the basis of the above findings, we construct a model suitable for identifying the stratigraphic boundary of the Anthropocene in the northeastern QXP and note that since the ecological environment in the northeastern QXP has entered the “Early Anthropocene”, the climate signals of certain physicochemical indicators in sediments are gradually becoming weaker, whereas the signals of human activities are becoming stronger.展开更多
To better analyse and understand the causes of Northwest China(NW China)arid climate formation,firstly the dry and wet standards were chosen and the yearly dry and wet grades on the north side of Qinghai-Xizang Platea...To better analyse and understand the causes of Northwest China(NW China)arid climate formation,firstly the dry and wet standards were chosen and the yearly dry and wet grades on the north side of Qinghai-Xizang Plateau(hereafter NSQXP)in summers were classified utilizing the rainfall data of five stations over the area in June-August of 1952—1990.Then the differences between the vertical motion over the Qinghai-Xizang Plateau(QXP)and NSQXP in dry and wet summers were comparatively analyzed using the ECMWF's gridded data of June—August of 1979 —1986.Finally the connection between the QXP surface thermal condition and the dry and wet summers on the NSQXP was discussed as well. The main results are the following:(1)the dry and wet standards taking the rainfall standard deviation as criterion are suitable for the arid climate area;(2)the QXP may be,to some extent. responsible for the environment background of Middle Asia,NW China and North China arid climate areas;(3)there are the striking differences between the dominant vertical motion over the QXP and NSQXP in the dry and wet summers of NSQXP:(4)the QXP surface thermal condition is.to a great extent,responsible for the year—to—year variation of NW China arid climate as well.展开更多
文摘Qinghai Lake is the largest inland lake in China. It is a closed-drainage saline lake located at 3194m above sea level in the northeastern Qinghai-Xizang (Tibet) Plateau. Qinghai Lake region, about 36°15' -38°20' N and 97°50, - 101°20' E,is a closed basin
基金Supported by the National Natural Science Foundation of China(U2442207 and 42075115)。
文摘Spring land surface temperature/subsurface soil temperature over the Qinghai-Xizang Plateau(QXP)substantially impacts downstream precipitation on subseasonal timescales.However,how well can climate models reproduce this impact and its assoicated interannual variation remains unclear.This study utilized the Regional Climate Model(Reg CM)Version 4.7 coupled with the Community Land Model(CLM)Version 4.5(Reg CM4.7-CLM4.5)to investigate the impact of May QXP soil temperature anomalies on June precipitation in eastern China.Causes for different precipitation responses to land surface/subsurface conditions and atmospheric background states in four years were analyzed.The results indicate that warm surface and soil temperature anomalies over the QXP in May led to increased precipitation in the southern Yangtze River basin(SYRB)in June.Due to soil temperature memory,the QXP warming persisted into June,sustaining a negative geopotential height anomaly at 500 h Pa above the QXP.Concurrently,negative and positive height anomalies developed over northern China and the Sea of Japan.The corresponding cyclonic anomaly in the mid-to-lower troposphere over QXP enhanced monsoonal moisture transport in May,and the persistent soil temperature anomaly over QXP sustained moisture convergence over southern China in June,resulting in increased precipitation there.Of the four years examined,both the precipitation response in the SYRB and the intensity of the associated wave train pattern are the strongest in 1998.The combined effect of land surface conditions in May and the atmospheric circulation background in June influenced the precipitation responses.Thermal conditions affected snow cover variations and consequently the radiative balance in the western QXP,causing stronger low-level atmospheric responses in 1998 compared to other years.Additionally,the position of the westerly jet influenced the propagation of atmospheric anomalies,contributing to the different responses in the mid-to-high troposphere.The above findings underscore the role of spring soil temperature anomalies over the QXP as a source of predictability for precipitation in eastern China at the subseasonal timescale.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42171160, 42225105, 42071115, 41972193)。
文摘In current research on the Anthropocene, assessing the impact of human activities via stratigraphic records of sediments and demarcating the Anthropocene epoch globally are critical scientific issues that urgently need to be addressed. The northeastern Qinghai-Xizang Plateau(QXP), where humans first settled permanently in large numbers in the QXP, has varying sedimentary environments that are extremely sensitive to human activities. In contrast to other regions of the QXP, the northeastern sector boasts a richer array of climatic and environmental reconstruction sequences. This distinctive feature renders it an exemplary locale for investigating the stratigraphic boundary of the Anthropocene. Through in-depth analysis and integration of existing paleoclimate and paleoenvironment sequences in the northeastern QXP, we draw the following conclusions:(1) Throughout the past millennium, the impact of human activities on the environment of the northeastern QXP has become increasingly significant, especially in the past 200–300 years, gradually overshadowing climatic factors.(2) Since AD 1950,multiple physicochemical indicators related to human activities in the northeastern QXP have shown exponential growth,forming a distinct peak within the past millennium and clearly depicting the global “Great Acceleration” phenomenon and its development process.(3) Intensified human activities have driven swift environmental shifts and “decoupled” the interplay between climatic variations and the ecological environment, propelling the northeastern QXP into the “Early Anthropocene”from the “Late Holocene”. On the basis of the above findings, we construct a model suitable for identifying the stratigraphic boundary of the Anthropocene in the northeastern QXP and note that since the ecological environment in the northeastern QXP has entered the “Early Anthropocene”, the climate signals of certain physicochemical indicators in sediments are gradually becoming weaker, whereas the signals of human activities are becoming stronger.
基金This work was supported by both the National Natural Science Foundation of China under Grant 49605067 Prominent Young Scientist Project in West China of Chinese Academy of Sciences.
文摘To better analyse and understand the causes of Northwest China(NW China)arid climate formation,firstly the dry and wet standards were chosen and the yearly dry and wet grades on the north side of Qinghai-Xizang Plateau(hereafter NSQXP)in summers were classified utilizing the rainfall data of five stations over the area in June-August of 1952—1990.Then the differences between the vertical motion over the Qinghai-Xizang Plateau(QXP)and NSQXP in dry and wet summers were comparatively analyzed using the ECMWF's gridded data of June—August of 1979 —1986.Finally the connection between the QXP surface thermal condition and the dry and wet summers on the NSQXP was discussed as well. The main results are the following:(1)the dry and wet standards taking the rainfall standard deviation as criterion are suitable for the arid climate area;(2)the QXP may be,to some extent. responsible for the environment background of Middle Asia,NW China and North China arid climate areas;(3)there are the striking differences between the dominant vertical motion over the QXP and NSQXP in the dry and wet summers of NSQXP:(4)the QXP surface thermal condition is.to a great extent,responsible for the year—to—year variation of NW China arid climate as well.
